论文部分内容阅读
目的:感染负荷被认为是动脉粥样硬化(AS)新的独立危险因素。金黄色葡萄球菌(S.aureus)是临床常见的致病菌之一。本课题组前期研究发现,金黄色葡萄球菌超抗原样蛋白-5(SSL5)可以激活血小板。我们推测,SSL5可能通过激活血小板而诱发炎症反应,探讨其机制可以为阐明感染负荷在AS中的作用提供新的实验证据。方法:体外培养人外周血单核细胞及THP-1细胞,以SSL5激活血小板所产生的微粒(SSL5-PMPs)作用于上述细胞。结果:SSL5-PMPs呈时间和剂量依赖性地促进单核细胞IL-1β、TNF-α、MCP-1和MMP-9的表达;并促进MCP-1诱导的单核细胞迁移;阻断CD40L与CD40的相互作用,可以部分抑制SSL5-PMPs诱导单核细胞产生炎症介质;以si RNA下调单核细胞CD40或TRAF6基因的表达,导致SSL5-PMPs诱导单核细胞炎症介质的产生减少,并抑制NF-κB p65亚单位的磷酸化及核转位;阻断TLR4信号通路对SSL5-PMPs诱导单核细胞释放炎症介质没有影响。结论:SSL5可以激活血小板并产生PMPs;SSL5-PMPs与单核细胞结合,且主要与外周血中的具有促炎作用的单核细胞结合,促进炎性细胞因子的释放,CD40-TRAF6-NF-κB信号通路主要参与了这一过程。本研究为阐明感染负荷的致动脉粥样硬化机制提供了依据。
Purpose: Infection load is considered as a new independent risk factor for atherosclerosis (AS). S. aureus is one of the common clinical pathogens. The previous study of our group found that Staphylococcus aureus superantigen-like protein-5 (SSL5) can activate platelets. We hypothesize that SSL5 may induce inflammatory responses by activating platelets and that its mechanism may provide new experimental evidence for clarifying the role of infection burden in AS. METHODS: Human peripheral blood mononuclear cells and THP-1 cells were cultured in vitro and treated with SSL5-PMPs via SSL5-activated platelets. Results: SSL5-PMPs promoted the expression of IL-1β, TNF-α, MCP-1 and MMP-9 in monocytes in a time- and dose-dependent manner and promoted the monocyte migration induced by MCP-1; CD40 interaction could partially inhibit the production of inflammatory mediators by monocytes induced by SSL5-PMPs. Down-regulation of monocyte CD40 or TRAF6 expression by si RNA resulted in decreased production of monocyte inflammatory mediators by SSL5-PMPs and inhibition of NF -κB p65 subunit phosphorylation and nuclear translocation; block TLR4 signaling pathway SSL5-PMPs-induced monocyte release of inflammatory mediators has no effect. Conclusion: SSL5 can activate platelets and produce PMPs. SSL5-PMPs bind to monocytes and mainly bind to proinflammatory monocytes in peripheral blood to promote the release of inflammatory cytokines. CD40-TRAF6-NF- κB signaling pathway is mainly involved in this process. This study provides evidence for elucidating the atherogenic mechanism of infection burden.